Notes
This module defines locks to constitue critical sections by disabling interrupts based on their priority. This is accomplished by manipulating the Status.IPL bits via the View_IPL register.
Example
Lock all interrupts of priority level 4 or less.
uint32_t p = 4;
uint32_t x;
x = ao_sys_lock_ir(p);
{
// ...
// Critical section.
// Interrupts are disabled up to and including priority level p.
// ...
}
ao_sys_unlock_ir(x);
Include
stdint.h |
xc.h |
Functions
ao_sys_lock_ir
#define ao_sys_lock_ir(p) \
({ \
uint32_t x0 = _CP0_GET_VIEW_IPL(); \
uint32_t x1 = (p) << 2; \
\
if (x0 < x1) \
{ \
_CP0_SET_VIEW_IPL(x1); \
} \
\
x0; \
})
Enters a critical section. This function disables all interrupts whose priority is not greater than p by manipulating the Status.IPL bits.
ao_sys_unlock_ir
#define ao_sys_unlock_ir(x) \
{ \
_CP0_SET_VIEW_IPL(x); \
}
Exits a critical section. This function restores the previous value of the Status.IPL bits.